论文标题
从高电场下的金属表面上的从头静置空置形成能和动力学
Ab initio vacancy formation energies and kinetics at metal surfaces under high electric field
论文作者
论文摘要
记录场离子显微镜图像在蒸发条件下，随后重建了基本原子构型，称为三维场离子显微镜（3D-FIM）是能够以原子量表解决结晶缺陷的少数技术之一。但是，观察到的空缺及其起源的量化仍然是一个争论的问题。有人建议在3D-FIM中使用的高电场（1-5 V/Å）可能引入人工空缺。为了研究这种影响，我们使用了密度功能理论（DFT）模拟。用（971）表面取向在重复的平板接近中对带有扭结的逐步NI和PT表面进行了建模。使用广义偶极校正，在平板的一侧引入了高达4 V/Å的静电场。与提出的相反，我们表明，与无现场的情况相比，电气金属表面上空缺的形成更加困难。我们还发现，电场可以将动力学障碍引入潜在的空位净化机制。我们通过与现场蒸发模型的见解进行比较来合理化这些发现。
Recording field ion microscope images under field evaporating conditions and subsequently reconstructing the underlying atomic configuration, called three-dimensional field ion microscopy (3D-FIM) is one of the few techniques capable of resolving crystalline defects at an atomic scale. However, the quantification of the observed vacancies and their origins are still a matter of debate. It was suggested that high electric fields (1-5 V/Å) used in 3D-FIM could introduce artefact vacancies. To investigate such effects, we used density functional theory (DFT) simulations. Stepped Ni and Pt surfaces with kinks were modelled in the repeated slab approach with a (971) surface orientation. An electrostatic field of up to 4 V/Å was introduced on one side of the slab using the generalized dipole correction. Contrary to what was proposed, we show that the formation of vacancies on the electrified metal surface is more difficult compared to a field-free case. We also find that the electric field can introduce kinetic barriers to a potential vacancy-annihilation mechanism. We rationalize these findings by comparing to insights from field evaporation models.
